Variations in the morphological and physiological characteristics of red blood cells in a patient's blood provide valuable information concerning the pathological condition of many specific types of red cell disorders or anemias. In diagnosing such disorders, the mean cellular hemoglobin concentration (MCHC) and the mean cell volume (MCV) may be measured to provide valuable insight into the condition of a patient. Such information may be used in conjunction with the microscopic evaluation of the distribution of sizes, shapes and color of red cells in a stained blood smear by a trained hematologist and with other biochemical tests. Variations in the refractive index of individual red cells are highly correlated with their hemoglobin concentration, and this information can be combined with size measurements to provide diagnostic value. For example, in microcytic anemias, the size of the red cells and, therefore, also the MCV are significantly reduced, but the optical density (related to the refractive index) and the MCHC are somewhat elevated. In megaloblastic anemias, both the size (macrocytes) and the MCHC are somewhat increased.
This disclosure relates in part to a method for determining the volume and/or hemoglobin content of individual red blood cells using a hematology analyzer, and a hematology analyzer for performing the method.